dog parks?

I have a 4 lb maltese and I would love to give her a big grass feild to run in but i’m scared of other dogs. Shes almost a year and is super tiny. I also want somewhere fenced in so she can run freely without me worrying of her getting to far. Are dog parks a good idea? I’ve heard many mixed opinions and I’m worried about a larger dog coming and im unable to recall her in time (im still working on it its pretty good, she always comes but she can be slow sometimes.)